Earth's bigger, older brother: planet Kapteyn b - Video

An artist’s rendition of Kapteyn’s star with its two planets in the halo around the Milky Way. 

Source: ph.qmul.ac.uk/ancient-worlds-around-kapteyns-star

We now know of a potentially habitable planet five times the size of Earth that has existed for more than twice as long.

A mere thirteen light years away, Kapteyn b is now the oldest known possibly rocky planet in a habitable zone.

This 5-Earth-mass planet orbits swiftly: once every 48 days around its parent star. Kapteyn itself is no slouch: it flies across the sky faster than almost any other nearby star.

The whole system-Kapteyn's star with its two recently discovered planets b and c-is a long way off from where it first formed outside our galaxy.

Discovered in late 1890's by the astronomer and cosmologist Jacob Cornelius Kapteyn, Kapteyn is an M1 red dwarf: a cool, small star, the most common type of star in our Galaxy.

While our Sun is between five and six thousand degrees Kelvin at its surface temperature, Kapteyn's surface is more like 3500 degrees K.

In addition to being cooler, Kaptyn is also less massive: about 1/3rd the mass of the Sun. Also in contrast to our 4.6 billion year-young Sun, Kapteyn's star is likely quite a bit older.

Kapteyn is thought to be a member of an ancient group that formed in the early days of the Universe.

These primordial stars now live in a halo just beyond the inner boundary of our galaxy. The halo objects, some of which are up to 13 billion years old, have been yanked across the sky to their present positions by cataclysmic galactic merging events that began in the early days of the Milky way.

This forced migration continues to affect their behavior. Kapteyn's star is flying away from us at 245 km (152 miles) per second.

It is also moving across the sky so quickly that in 3500 years it will leave the constellation Pictor and enter Dorado, the next constellation to the southwest.

Because of its temperature and speed, Kapteyn is known as a high-velocity, low-luminosity halo star.


These M dwarf stars make great targets in the hunt for exoplanets. We can, quite literally, watch them walk across the sky.

Planet-hunting using doppler shifts has improved to the point where we can measure the speeds of these particular stars to the one meter per second level: which corresponds to walking speed.

As a result, we can detect exoplanets a little larger than our own around nearby M class dwarf stars. Kapteyn b is just such an exoplanet.

Kapteyn makes an even better target than most because it is so incredibly close. There are only two-dozen stars closer to us than Kapteyn.

It is by far the closest of all the halo stars. Even so, twenty astronomers on three continents combined ten years of data from three large large telescopes to resolve the Doppler signals that we are now calling Kapteyn b and c, orbiting with periods of 48 and 120 days, respectively.

"We were surprised to find planets orbiting Kapteyn's star," said lead author Dr. Anglada-Escudé from Queen Mary University of London's School of Physics and Astronomy.

"Previous data showed some moderate excess of variability, so we were looking for very short period planets when the new signals showed up loud and clear."

Chelyabinsk meteorite part of much bigger celestial body

The Chelyabinsk meteorite that exploded on February 15, 2013, in the Chelyabinsk area was part of a bigger celestial body and came off it as a result of the impact.

The statement was published on a website called Scientific Reports after a team of scientists, including Russians, conducted research.

The scientists studied the chemical composition of the meteorite's fragments and found out that they contain jade.

This mineral is formed under high pressure and temperature, scientists say.

They also say that the form of the jade fragments show that they were formed as a result of a collision of two asteroids.

The asteroid, from which the meteorite came off, was at least 7,500 inches in diameter. The scientists are still ascertaining the trajectory of the both asteroids. They think that the collision occurred 250 million years ago.

"The impact could cut off the Chelyabinsk meteorite from a bigger celestial body and direct it to the Earth."

"This is a body from the circumterrestrial space that struck against the Earth and its trajectory has been studied well," Sin Ozawa from Tohoku University said.

The scientists think that the newly discovered data will help them foresee, whether particular celestial bodies can hit the Earth.

The team also comprised Russian scientists from Novosibirsk State University, Mineralogical Institute of the RAS Ural department and V.S. Sobolev Institute of Geology and Mineralogy of the Siberian Branch of the RAS.

The Chelyabinsk area saw an explosion of a meteorite on February 15, 2013. The flash of the explosion was seen by the citizens of the Tyumen, the Sverdlovsk, the Kurgan areas and the Republic of Bashkortostan.

The meteorite was 680 inches in diameter, weighted 10,000 tons and its speed was 6-18 miles per second.

More than 1,500 people suffered as a result of the explosion; the only such case in history.

Later, in October, the biggest fragment of the meteorite, weighting 1,430 pounds, was recovered from the bottom of Lake Chebarkul.

Lake Chebarkul

Plutonium and Caesium: Nuclear-test legacy in stratosphere bigger than thought

Plutonium cycle in the atmosphere. Credit: : J.A. Corcho Alvarado

Levels of radioactive plutonium in Earth's stratosphere from nuclear tests and accidents is higher than previously thought, but probably not dangerous to humans, scientists in Switzerland said Tuesday.

It was previously thought that plutonium radionuclides—radioactive atoms which can take decades or thousands of years to degrade—were present in the stratosphere only at negligible levels.

It was also believed that levels of these pollutants were higher in the troposphere, the layer of the atmosphere that is closest to the ground, than in the stratosphere.

Both ideas turn out to be wrong, according to the new study, whose authors also found no likelihood of a hazard to health.

Radiation levels in the stratosphere are "more than three orders of magnitude higher than previously thought," study co-author Jose Corcho of the Swiss Federal Office for Civil Protection told reporters.

The team also found that volcanic eruptions may shift those pollutants from the stratosphere into the troposphere, closer to Earth.

But Corcho said there was no evidence of danger.

"The levels of plutonium and (caesium) currently found in the stratosphere are low, and comparable to the levels measured at ground level air (troposphere) at the end of the sixties and in the seventies," he explained.

The aerosol collection devices mounted on the wings of a Tiger (F5E/F), aircraft of the Swiss Air Force. 

Credit: Swiss Federal Office of Public Health

"Although I'm not a health specialist, I would say that the current levels of plutonium found in the stratosphere do not represent a risk for the population."

The study, published in the journal Nature Communication, said the radioactive particles in the stratosphere mainly came from above-ground nuclear weapons tests in the 1950s and early 1960s.

Other sources were the burn-up of an ill-fated US navigation satellite in 1964 that spilled its plutonium fuel into the atmosphere, and nuclear power plant accidents like Chernobyl and Fukushima.

The team used aerosol samples taken by Swiss military aircraft since the 1970s as part of the country's environmental surveillance programme.

More information: Paper: dx.doi.org/10.1038/ncomms4030

Yellowstone magma much bigger than thought

This graphic provided by University of Utah geophysicists shows the first large-scale picture of the electrical conductivity of the gigantic underground plume of hot and partly molten rock that feeds the Yellowstone supervolcano. 

The plume of molten rock feeding the supervolcano under the surface of Yellowstone National Park is much larger than previously thought, according to University of Utah geophysicists whose findings will be published in Geophysical Research Letters. 

AP Photo/University of Utah

The hot molten rock beneath Yellowstone National Park is 2 ½ times larger than previously estimated, meaning the park's supervolcano has the potential to erupt with a force about 2,000 times the size of Mount St. Helens, according to a new study.

By measuring seismic waves from earthquakes, scientists were able to map the magma chamber underneath the Yellowstone caldera as 55 miles (88.5 kilometers) long, lead author Jamie Farrell of the University of Utah said Monday.

The chamber is 18 miles (29 kilometers) wide and runs at depths from 3 to 9 miles (5 to 14 1/2 kilometers) below the earth, he added.

That means there is enough volcanic material below the surface to match the largest of the supervolcano's three eruptions over the last 2.1 million years, Farrell said.

The largest blast—the volcano's first—was 2,000 times the size of the 1980 eruption of Mount St. Helens in Washington state.

A similar one would spew large amounts of volcanic material in the atmosphere, where it would circle the earth, he said.

"It would be a global event," Farrell said. "There would be a lot of destruction and a lot of impacts around the globe."

The last Yellowstone eruption happened 640,000 years ago, according to the U.S. Geological Survey. For years, observers tracking earthquake swarms under Yellowstone have warned the caldera is overdue to erupt.

A large earthquake at Yellowstone is much more likely than a volcano eruption, Farrell said.

The 7.5-magnitude Hebgen Lake earthquake killed 28 people there in 1959.

Farrell presented his findings last week to the American Geophysical Union. He said he is submitting it to a scholarly journal for peer review and publication.

Brigham Young University geology professor Eric Christiansen said the study by Farrell and University of Utah Professor Bob Smith is very important to understanding the evolution of large volcanos such as Yellowstone's.

"It helps us understand the active system," Christiansen said.

"It's not at the point where we need to worry about an imminent eruption, but every piece of information we have will prepare us for that eventuality."

Earth and Venus: Exoplanet Habitable Zone Around Sunlike Stars Bigger

The Earth and Venus, although not very different in size, have had a very different climate history. 

In the future, the Earth may look like Venus. 

Credit: Jeremy Leconte

Earth's place in the solar system is just right.

It's not too hot, like Venus, and it's not too cold, like Mars, and this "Goldilocks zone" of habitability around other stars like the sun just might be bigger than thought, scientists say.

A new study, unveiled today (Dec. 11), expands the habitable zone — the sweet spot in a solar system where liquid water and therefore life could potentially exist — surrounding stars like the sun.

Previous studies on the habitability zone around sunlike stars have placed the innermost edge of so-called Goldilocks zoneat about 0.99 AU (1 AU, or astronomical unit, is the average distance from Earth to the sun, about 93 million miles, or 150 million kilometers).

But a new computer model study pushes that border closer to its parent star, to a distance of about 0.95 AU (about 88 million miles, or 142 million kilometers).

The study in the journal Nature, led by Jeremy Leconte, now a postdoc at the Canadian Institute for Theoretical Astrophysics of the University of Toronto, used 3D computer modeling to find that the runaway greenhouse effect isn't an issue unless the planet is less than 0.95 AU from its star.

The new inner boundary for habitable zones might not make a big difference for scientists trying to determine if an alien planet is habitable, but it does make a big difference for future life on Earth, Leconte said.

Eventually, the sun will become brighter, heating the Earth and potentially creating a runaway greenhouse effect — a feedback loop that eventually causes a planet's oceans to boil away. But that eventuality is long way off, and it may now actually be farther off than previously expected, Leconte suggests.

"For example, if we believe that the limit is at 0.99, it means that Earth would start losing oceans around 150 million years from now," Leconte told reporters.

"Now, with our new estimate, it's not 150 million years, but it's actually 1 billion years, so almost an order of magnitude bigger."



More Information: 
Increased insolation threshold for runaway greenhouse processes on Earth-like planets doi:10.1038/nature12827

On Reflection, A Bigger Brain

“We introspect when we think about our own thoughts, feelings, or the decisions we have made,” says Steve Fleming, joint first author of the study and a researcher at University College London. “It’s something we do all the time, but some people are better at it than others. Even if we don’t get feedback when we make a choice, we often know intuitively if it’s a good or a bad decision.”

Full story at Futurity.